Protection of surfaces



Sept. 14, 1943. w. A. BEH

PROTECTION 0F SURFACES Filed April 27, 1938 mVENroR.

BY VZZF y ummm/ Patented Sept. 14, 1943 UNITED STATES PATENT OFFICE PROTECTION OF SURFACES Application April 27, 1938, Serial No. 204,631

' 3 Claims.

This invention relates to the protection of surfaces and particularly to the protection or separation of raw or partially vulcanized rubber surfaces. It has been customary to use for this latter purpose a strong cotton or linen fabric provided with a smooth glaze, known as Holland cloth. While this material is smooth and strong enough to permit it to be stripped from the rubber surface, it adheres very tightly and some of the glaze is likely to remain on the rubber surface from which it is very diicult to remove, without contaminating or damaging that surface. If these particles of glaze are not completely removed from the rubber surface, the latter is unsuitable for use. Furthermore, Holland cloth is very expensive.

It has been proposed to use cardboard or papers of various kinds for this purpose. These attempt-s have been unsuccessful since in order to make them impervious to gas, oil, water, organic solvents, etc., which would damage the surface of the rubber, it has been necessary to ll the paper with various organic or inorganic llers with subsequent calendering. These treatments are expensive and in spite of them, difliculty is experienced in completely stripping the paper from the rubber surface because the paper frequently tears and due to its fibrous structure, leaves fragments which are diflicult to remove.

It has also been proposed to use glassine paper for this purpose, but this is unsatisfactory since this material retains the fibrous character of the paper, tearing .easily and likewise leaving fragments on the surface of the rubber.

It is the object of this invention to use as a protective covering for tacky surfaces an article of manufacture which is cheap, has the necessary strength as well as resistance of gas, oil, organic solvents, etc., and can be readily stripped from a tacky surface such as that of raw or partially cured rubber without tearing .or leaving fragments on the surface.

In accordance with this invention, it has been found that regenerated cellulose sheeting to which has been applied a relatively large amount of a sizing agent as a protective, separable covering for tacky surfaces can be used. Sheets of regenerated cellulose surfaced with a thin layer of a normally solid, wax or wax-like substance and/ or a soap or soap-like substance show markedly reduced adhesion to a tacky surface, such as that of raw rubber, and these sheets can be readily stripped from the surface of the rubber without leaving any fragments behind.

In'the practice of this invention, a highly sized regenerated cellulose sheet may be used directly, or it may rst be laminated to itself or to a sheet of suitable material such as paper or cloth. This laminated product will have increased strength and resistance to tearing and will betteprotect the surface to whichit is applied.

For the purposes of illustration, this description has been limited to the use of highly sized regenerated cellulose sheeting alone or laminated to itself or to paper for the protection of the raw or partially cured surfaces of rubber.

The invention will be more clearly understood by reference to the following description taken in connection with the accompanying drawing in which:

Figure l is a face 4view of a tire patch having applied thereto a covering which is constructed according to one modification of this invention.

Figure 2 is a cross sectional view of the structure shown in Figure 1 on a larger scale.

Figure 3 shows another manner in which the invention may be utilized for the separation and protection of tacky rubber surfaces.

Figures 4, 5, 6, and 7 are cross sectional views on an enlarged scale of other laminated structures involving the invention which can be used for separating or protecting tacky surfaces.

As is well known, a tire patch is composed of a body l formed of cured rubber and a surface 2 of uncured or partially cured rubber which is designed to be vulcanized when the patch is used. This tacky surface 2 must be protected until ready for use to prevent contamination of the surface or cohesion of adjacent patches. According to this invention, a sheet of highly sized regenerated cellulose 4 which has been laminated to a backing 3 of ordinary kraft paper, cloth, or other suitable material is used for the protection of this surface. The two sheets may be united by any suitable adhesive 5, but itis preferable to use a waterproof adhesive as this increases the resistance of the laminated material to moisture, etc. A convenient and cheap adhesive for this purpose is asphalt although many others such as hide glues, molten resins such as Glyptal resins, polyvinyl alcohol, etc., are satisfactory.

The protective material which is used in the preparation of a tirejpatch may be conveniently prepared by severalA well known methods of lamination. The adhesive 5, such as asphalt, may be coated on a web of ordinary kraft paper and this united to a web of highly sized regenerated cellulose sheeting by subjecting them to heat and pressure. This can conveniently be done by passing the two webs between heated previously.

rollers. This laminated sheeting'is then pressed upon the tacky surface of the rubber with the surface of the regenerated cellulose sheeting Vin contact with the rubber surface. This protective material adheres sufficiently well to the tacky rubber surface to prevent accidental displacement before the use of the tire patch. The rubber sheet and protective sheet may then be cut into convenient sizes for tire patches. It is to be noted that this lamination of the regenerated cellulose sheeting to the backing material may be carried out as one step in the manufacture of the tire patch, or it may have been performed when it is desired to use the tire patch, a corner or edge of the laminated protective material may be readily grasped and the whole ksheet stripped from the rubber patch and discarded. The tacky, uncontaminated, raw rubber surface of the patch is then exposed and can be readily used for its intended purpose.

Regenerated cellulose sheeting is prepared commercially by extruding a cellulose xanthate solution (viscose) into coagulating and/or regenerating baths followed by washing, bleaching, and other purifying treatments. The wet or gel sheet is then impregnated with an aqueous solution of a suitable softener and finally dried by passing the softened sheet over a series of heated rolls. Such sheets are known to the trade as plain sheets of regenerated cellulose, as differentiated from the further treated sheets such as the lacquered, waterproof or moistureproof varieties. This sheeting is impermeable to oils, organic solvents, etc., .but is not appreciably moistureprooi'.v Y i The regenerated cellulose sheeting for the purpose of this invention must be highly sized. Most conveniently, the size may be applied during the manufacture in the form of an aqueous dispersion and/or solution during the softening treatment, that is, in the treating bath containing the aqueous softener solution and just prior to drying. Before entering the drier, the excess size, together with the excess softener solution, may be removed by suitable squeeze rolls, scraper rods, or doctor knives. The amount of size which is applied is controlled by adjusting the concentration of the size in the treating bath or by varying the amount of the excess removed. If it is desired to apply the sizing agent separately, the lm may be treated with the softener bath, the excess removed and the size applied by dip rolls, sprays or the like. This latter method is preferred in cases where it is desired to size the lm on only one side, thus facilitating subsequent lamination of the unsized side to a base such as paper or fabric.

The size may also be applied to the dried lm. This may be conveniently done by passing the dried film through a bath containing water o'r an aqueous solution of the softener until thoroughly wetted. The size may then be applied to i this rewet film as described above for the treatment of a gel film.

Under certain circumstances, it may be desirable to apply the size to a dried lm by dissolving the size in a volatile organic solvent, coating this solution on the nlm and passing the lm through a drier to remove the solvent.

The following examples will 4illustrate. methods of preparation of highly sized regenerated cellulose sheeting useful in accordance with this lnventio Example I A sheet of gel regenerated cellulose of such thickness as will give a final thickness of about 0.0009 inch is passed through an aqueous softening bath which contains in addition to the softening agent, the desired amount of the sizing agent. The bath, in this instance, contains 6% to '1% glycerol and about 0.5% dispersed carnauba wax, the latter having been supplied Example II A sheet of gel regenerated cellulose is treated as in Example I by passing it through a bath containing 6% to 7% glycerin and 0.4% of an aqueous sodium stearate-silicate size .mixture This size mixture is prepared by mixing together equal weightsof stearic acid and a 37% aqueous solution of sodium silicate. The mixture is then heated and allowed to react before addition to the bath.

After drying to a moisture content of 5%, a nal transparent sheet of softened, sized regenerated cellulose is obtained which contains in addition to cellulose and moisture, about 19% glycerol and 0.15% to 0.75% of the size (based on the bone dry weight of the product).

Example III A sheet of gel regenerated cellulose containing softener is sprayed on one side with a 1% aqueous triethanolamine stearate-stearic arid mixture. This mixture may be prepared by mixing together, in water, approximately equal weights of triethanolamine stearate and stearic acid. The sprayed film is then passed through the drier in the same manner as described in Example I. The final transparent sheet of softened, sized regenerated cellulose thus obtained contains in addition to the cellulose, moisture and softener, 0.1% to 0.4% of the thiethanolamine stearate on one siue of the film (based on the bone dry weight of the product).

Example IV A sheet of dried regenerated cellulose containing about 6% moisture and about 19% glycerol as a softener is passed through a bath containing a 0.15% solution of stearic acid in toluene. The excess is removed by squeeze rolls, scraper rods or doctor knives.. duced into a chamber through which air is circulated and the solvent removed at an elevated temperature. The transparent. sized and softened sheet of regenerated cellulose obtained contains in addition. to the cellulose, moisture and softener, from 0.1 to 0.4% stearic acid.

Other normally solid wax or wax-like substances and/or a soap or soap-like substance may also be used as sizing agents. Substances which are waxes, wax-like or approach waxlnesc and which may be used are hydrogenated oiJ'e, e. g., hydrogenated castor oil. higher fatty acids,

The coated film is then introy I may be employed.

etable and/or synthetic waxes of wax-like substances.

Among the soap materials suitable for use as sizing materials are sodium or potassium salts of other fatty acids such as oleic, lauric, ricinoleic, etc., other triethanolamine soaps, the sodium or other alkali metal sulfuric acid esters of the higher fatty alcohols such as stearyl, oleyl, lauryl, cetyl and myristyl alcohols, the sulfonated oils and their salts, e. g. sodium petroleum sulfonate, or similar substances.

lMixtures of the substances mentioned .above One or more substances of the same class or different classes may be combined depending on the properties desired. vIt may be desirable to employ certain combinations or concentrations of the sizing components which will render the surfaces of the regenerated cellulose sheeting non-receptive to ordinary adhesives. In these cases, where it is desired to laminate the regenerated cellulose sheet to a base, it will usually be desirable to apply the size to only one side of the sheet and to laminate the unsized side to the base.

`In Figure 3 is shown a rollv body 6 enrolled about a shaft or core 1. This roll body is made up of alternate convolutions of tacky, raw rubber sheeting 9 and highly sized regenerated cellulose sheeting 8. The interwound regenerated cellulose sheeting, highly sized on both sides, protects and separates the surfaces of the raw rubber sheeting.

In'place of a sheet of highly sized regenerated cellulose alone or laminated to itself or to a sheet of paper or fabric, other laminated materials,

-such as that shown in Figure 4, may be employed.

This comprises a reinforcing layer 3 of paper or fabric, to both sides of which are laminated, by means of the adhesive 5, sheets of regenerated cellulose 4 winch are highly sized on both sides or only on their outer surface, i. e., the surface not laminated to the base 3. Since both surfaces of this laminated material comprise highly sized regenerated cellulose, this product serves .the same purpose as the unlaminated sheet or of two sheets of regenerated cellulose laminated by an adhesive, but has the additional strength and protective value due to the lamination to the reinforcing layer 3. It can be used for any purpose for which the unlaminated sheet is used and is especially effective as a separator in piles of raw rubber sheets.

In Figure 5 is shown a cross sectional View of a laminated protective material constructed in the same way as that shown in Figure 4 except that the highly sized regenerated cellulose is replaced on one side by a sheet of either normally sized, or unsized regenerated cellulose sheeting l0, or a sheet of the moistureproof or coated variety. This laminated material, like that having the highly sized regenerated cellulose laminated to only one side of the base, is adapted to contact tacky surfaces on only one'face. The selection of the sheet l which will be used on the outer surface will be dictated by the surface characteristics desired as well as its protective value against moisture, etc.

In Figure 6 is shown a cross sectional view of a laminated protective material comprising two sheets of highly sized regenerated cellulose 4 Y and 4' laminated together by means of an adhesive in which has been incorporated fibrous material. This modification fulfills the same function as the modification in which two sheets of highly sized regenerated cellulose sheeting are laminated together by means of an adhesive alone, but is greatly superior in strength due to the reinforcement of the disoriented fibers. For the same reason this product has the same utility as that material shown in Figure 4, the fiber adhesive mixture replacing the reinforcing layer 3 and eliminating one -laminating step. This fiber-adhesive mixture may be similarly used in the same manner to replace the reinforcing layer 3 in the modification shown in Figure 5 where regenerated cellulose sheets of different properties are used on the opposite surfaces.

The composition of this fiber-adhesive mixture may be varied widely. Various types of fibers such as cotton, cotton linters, sulflte pulp, kraft pulp, sisal, jute, hemp, etc., may be used with any adhesive suitable for the lamination without an admixture of pulp. The relative proportions depend in general on the reinforcement desired. For many purposes a mixture containing 20 to 25% brous material is satisfactory while for others greater and lesser amounts are used.

Should decorative eiects on this protective material be desired, colored or printed regenerated cellulose sheeting highly sized on one or both sides might be used. Similarly, many laminated constructions might be employed. In Figure 7 is shown a cross sectional view of a structure in which a highly sized regenerated cellulose sheet 4 is laminated to one side of a backing material 3 by an adhesive 5 as described previously. To the other side of the backing material 3 may be laminated a specially decorated sheet of regenerated cellulose l2 by means of the adhesive Ii. This sheet i2 may be colored or uncolored, transparent or opaque, printed or unprinted. These sheets in combination with the adhesive I l which may likewise be colored permit an almost unlimited number of color combinations. Similarly, it may be desirable to employ a transparent sheet of regenerated cellulose and a transparent adhesive so that any printing or other decorative effects on the base material 3 will be visible.

It is to be understood that the broad scope of the invention includes the use4 of regenerated cellulose films for the purpose described herein, where such films contain reinforcing fibers of any desired character such as may be mixed with the cellulosic solution, such as viscose, prior to the formation of the regenerated cellulose lrn. The use of such fibers for reinforcing the lm may be desired where a particularly tough or strong sheet is preferred.

It is apparent that the use of highly sized regenerated cellulose sheeting, either alone or laminated to another sheet of regenerated cellulose or other suitable support may be used for the protection of a large variety of tacky surfaces. While this invention has been described in terms of the protection of tacky rubber surfaces, various combinations and modications will give products which can be used for the protection cf tacky surfaces generally.

The use of this invention satisfies in an economical and enicient manner all of the functions required of a protective material such as Holland cloth. It is applicable for any purpose for which Holland cloth is used. The combination of the non-porous, non-fibrous character of regenerated cellulose, the smoothness of its surface, and its non-adhesivness due to the sizing treatment, make it highly adaptable for the protection and separation of tacky surfaces generally. Where added strength, protection, or decorative effects are desired, they may be easily secured by printing,v lamination or other decorations.

Parts, proportions and percentages referred to herein are intended to be parts, proportions and percentages by Weight, unless otherwise indicated.

Any modification of the invention which conforms to the spirit of the invention is intended to be included within the scope of the claims.

I claim:

1. An article comprising a material having a tacky surface of uncured or partially cured rubber and a protecting layer comprising smooth. iiat regenerated cellulose nlm having a highly sized surface in contact with said tacky surface.

2. An article comprising a material having a tacky surface of uncured or partially cured rubber and a protecting layer comprising smooth, nat regenerated cellulose nlm having a highly sized surface in contact with said tacky surface, said sizing being taken from a member of the class consisting of waxes'and soaps.

3. An article comprising a material having a tacky surface of rubber and a protecting layer comprising smooth, iiat regenerated cellulose film having a highly sized surface in contact with said tacky surface. said size consisting of 0.15% to 0.75% sodium stearate-silicate size mixture (based on the bone dry weight of the regenerated cellulose lm and its size).

- WARREN A. BEH.

CERTIFICATE oF CORRECTION. Patent No. 2,529,179. september 1u, 191,5.. AWARRENY ALBERT BEH.

It is hereby certified that error appears in the printed specification of the above numbered patent 'requiring correction as follows: Page l, first column, line 58', for the word "of" before *gas* read to; pega 2, second. column, line 5, after "final" insert --ry--g line 55-514., for "thiethgnolamine" read -triethano1amine; page 5, first column, line'5, for "of" 'after waxes read -or; and second column, line "(l|. for 'nonadhesivness read --non-adhesiveness; and that the said Letters Patent should be read with this correction therein that the seme may conform to the record of the case inthe ,Patent Office. i

signed and sealed this 26th-day of october, A. D. 1915.

Henry Van rsdale, (Seal) Acting Commissioner of Patents.' 

